The present invention relates to an electrical tooth cleaning apparatus, and, more particularly, to an electrical tooth cleaning apparatus in which the drive motor is fixedly held in position in the housing by means of a vibration dampening element.
In the tooth cleaning apparatus known from Swiss Patent No. 425,719, the drive motor is displaceably mounted at the rear housing portion and bears, on the one hand, at the front housing portion and, on the other hand, by means of a compression spring, at the base of the rear housing portion. Under the action of this compression spring, both of the housing portions, held together by a O-ring, are clamped together while compressing the O-ring. This results in a deformation of the O-ring which ensures a watertight closure. With this solution, the joining together of both housing portions is indeed relatively simple. However, certain constructional measures are still required for this purpose, such as the support of the motor at the front housing portion and the provision of a compression spring. These measures result in a more expensive fabrication and require a greater amount of time during assembly.
In U.S. Pat. No. 3,235,897 there is shown a solution wherein the drive motor has a protruding, rigid bead, which is fixedly clamped between both threadable interconnected housing portions. For sealing the housing interior, a sealing ring is inserted between the bead and the one housing portion, whereas at the opposite side, the bead bears directly at the other housing portion. The drive motor, which is fixed by means of the fixedly clamped bead in its fixedly determined position, is, however, rigidly mounted, so that the motor vibrations can be transmitted to the housing. Also, the relatively thin sealing ring is capable of changing very little as to these conditions.